The prior LCD display screen is to adhere a TFT substrate to a color filter substrate, as illustrated in FIG. 1, it comprises a backlight source 01 and a liquid crystal display panel 02. The liquid crystal display panel 02 comprises an upper substrate 021, a lower substrate 022 and a liquid crystal material 023. The upper substrate 021 comprises a black matrix 0201, and a red pixel region 0202, a green pixel region 0203 and a blue pixel region 0204 surrounded by black matrix patterns. A used white backlight is formed by mixing the yellow light and the blue light emitted by exciting a yttrium aluminum garnet (YAG) fluorescent powder using a blue chip, and the light emitting efficiency is low, the color is impure, and a relatively low color gamut is rendered after the filtration by the R\G\B of a color filter layer CF, and the color is not bright or real. Therefore, how to improve the performance has been a technical problem in the prior art.
The Quantum dot is generally nano particles composed of II-VI group or III-V group elements, and can emit fluorescent light after being excited. The light emitting spectrum can be controlled by varying the size of the quantum dot, and both the fluorescent intensity and the stability are fine, so it is a good photoluminescence material. There are a lot of quantum dots, and the representative ones are CdS/CdSe/CdTe/ZnO/ZnS/ZnSe/ZnTe and etc. in the II-VI group and GaAs, GaP, GaAs, GaSbi, HgS, HgSe, HgTe, InAs, InP, InSb, AlAs, AlP, AlSb and etc. in the III-V group. Quantum dots of the same material can emit different lights according to the produced size. Currently, the prior art already has the technical solution of applying quantum dot materials to a backlight source, which can improve the light emitting efficiency to a certain extent, but how to render a display device with a wide color gamut and high optical efficiency is still a technical problem in the prior art.